Aqueous herbicidal formulations of glufosinate-ammonium have been available for decades as crop protectants. Popular formulations include surfactants, which increase the biological activity of the herbicide. High concentration formulations are being sought as well for the numerous advantages they offer; for example, less packaging is needed than with low-concentration formulations, corresponding to reductions in the cost and inconveniences of production, transit, and storage. Preparation of spray liquors is also simplified by the smaller quantities of crop protectant that need to be handled. However, certain drawbacks have been observed in higher concentration formulations. For example, the biological activity of the active ingredient is dependent on the proportion of active ingredient to surfactant, but if the amount of surfactant is too high, the viscosity of the composition may become too high for easy handling or spraying. Product instability such as phase separation has also been a drawback of highly concentrated formulations. Phase separation is undesirable because the concentration of various essential ingredients is no longer uniform throughout the composition.
It would be desirable to provide a high-concentration herbicidal composition that overcomes the drawbacks of the prior art by demonstrating enhanced biological activity in a stable formulation without compromising viscosity requirements.